There continues to be great interest in developing new and improved contraceptives. While a variety of contraceptive products are currently available, each product is accompanied by certain drawbacks and/or risks. For example, condoms offer the best protection against sexually transmitted diseases (STD) including HIV, but they can tear and may cause irritation or allergic reactions. Oral contraceptives do not provide protection against STDs and are associated with a number of risks including nausea, changes in mood and weight, and acne. Further, for women who are part of a high risk category, such as over 35, overweight, a heavy smoker, diabetic, have high cholesterol or high blood pressure, there is an increased risk of serious side effects including a heart attack or stroke while taking oral contraceptives. Diaphragms require careful fitting and can lead to irritation, allergic reactions, urinary tract infections and in rare cases, toxic shock syndrome, when left in place longer the recommended time. Spermicides, such as Nonoxynol-9, are been associated with increased risk of vaginal or cervical infection, irritation, or ulceration and typically have a higher failure rates than other contraceptive methods.
In addition, reliable methods of contraception are still needed by many segments of the world's population, as many women do not have regular access to oral contraceptives, or may suffer adverse reactions to the hormones used in oral contraceptives. Thus, there remains a need for new contraceptives that are both safe and effective.